1. Field of the Invention
The present invention relates to a lithography apparatus that performs writing on a substrate with a charged particle beam, and an article manufacturing method using the same.
2. Description of the Related Art
Lithography apparatuses that perform writing on a substrate by controlling deflection scanning and blanking of charged particle beams such as electron beams are known. The lithography apparatuses may be employed as one of pattern forming technologies that is an alternative to optical exposure systems for the production or the like of a memory device of 4GDRAM or later with a line width of 0.1 μm or less. As an example of such a lithography apparatus, there is also known a multiple-beam type lithography apparatus that performs writing using a plurality of charged particle beams in order to achieve improvements in throughput. Such a lithography apparatus converts writing data, i.e., obtained vector pattern data (pattern data which is a collection of rectangular or trapezoids) into bitmap data so as to perform writing based on the converted bitmap data. Here, the written pattern (writing result) may not be formed in a desired shape due to forward scattering or backscattering of electron beams during writing processing. Thus, the initially set pattern data is subject to proximity effect correction processing such as changes in writing distribution by emphasizing the corners of pattern graphics, dividing pattern graphics, or the like in advance. When an assumption is made that the entire pattern data is corrected with respect to a subject to be processed, the correction processing may take several hours at present. The pattern data (corrected data) subjected to correction processing is stored after the pattern data has been validated by simulation. The lithography apparatus receives the corrected data and converts it into bitmap data to thereby perform conversion of the position or magnification of the data. Then, the lithography apparatus further converts the corrected data into binary data corresponding to ON/OFF of writing to be transmitted to a blanking deflector to thereby finally perform writing. Japanese Patent Laid-Open No. 2005-79112 discloses an electron beam writing data editing method that is associated with proximity effect correction processing and extracts a part of micro graphics included in writing data as the editing target to thereby reflect it to original writing data after editing in order to improve correction accuracy.
However, even when pattern data is subject to the proximity effect correction processing as disclosed in Japanese Patent Laid-Open No. 2005-79112, the writing result may not be as desired because the writing result includes error factors of proximity effect correction due to changes in a material such as a resist, an antireflection film, or the like, processing for coating/development a resist, or the like. When the actual writing result is not as desired, the process needs to return to initial pattern data to re-edit pattern graphics. In other words, in this case, proximity effect correction processing or data conversion processing need to be repeated in accordance with changes in initial pattern data, resulting in an increase in data transfer time or writing processing time for bitmapping.